In mobile communication, a terminal device communicates with a network device through an air interface. An “air interface” is a wireless transmission specification or an access mode (Access Modes) between a terminal device and a network device. Different air interfaces determine features of wireless communication, for example, a delay, a transmission rate, and coverage.
Different services have different requirements for wireless communication. For example, for a remote mechanical control service, an optimal connection service requires a low delay, a high bandwidth, and coverage of a particular geographic area in wireless communication. For another example, for a media transmission service, an optimal connection service requires a relatively high transmission rate, but has a low requirement for a delay in wireless communication.
For example, FIG. 1 is a comparison diagram of an example of a configuration of an air interface in a broadband service (for example, a media transmission service) and an example of a configuration of an air interface in an ultra short delay service (for example, an online game or a video conference). As shown in FIG. 1, the broadband service has a relatively low requirement for a delay, a length of a subframe is relatively large, and a control channel appears on first few symbols of each subframe. Therefore, an appearance period of a control channel is relatively long, and a frequency of control signaling is relatively low, resulting in a high RTT delay in signaling transmission. However, because a resource block on a data channel is relatively large, a granularity of a resource allocated each time by a control channel is also relatively large, and it is relatively suitable for a non-short delay broadband large datagram service. In addition, because appearance frequency of a control channel is relatively low, frequency of listening to a control channel by a terminal is also reduced, so that it is more energy-saving. By comparison, the ultra short delay service has a relatively high requirement for a delay. Therefore, a subframe is shortened, and frequency of a control channel becomes higher. Compared with the broadband service, within a same time period, the short delay service may have more chances to deliver control signaling, so that the service is scheduled in a more timely manner. Short delay scheduling may also require simpler encoding and decoding on a control channel and a data channel, so as to lower a processing delay.
As can be learned, it is very difficult to implement compatibility between the foregoing two services in a same system without mutual impact. Therefore, for the ultra short delay service, the air interface needs to be redesigned, and the configuration of the air interface in the broadband service cannot be used.
In addition, due to a standardization attribute of an air interface, if a network device or a terminal device is changed unilaterally, the two parties cannot complete wireless communication. Therefore, to meet requirements of different services for wireless communication, different communication systems or networks need to be configured for different services, to provide different air interfaces.
As mobile communication technologies are upgraded, requirements for new services are growing. To meet the requirements, based on the prior art, communication systems need to be separately established for different services, resulting in a significant increase in operational costs, and making it difficult to respond to a personalized requirement for an air interface in time.